Patent GB-954257-A (GB)
Title: Remote control system for railway vehicles
IPC: B61L23/22
Filed: 1961-11-13
Abstract: 954,257. Automatic train control systems. GENERAL RAILWAY SIGNAL CO. Nov. 13, 1961 [Dec. 9, 1960], No. 40489/61. Heading B7N. In a railway signalling system for the control of movement in both directions of manned or unmanned trains over a single stretch of track, including passing sidings, which is divided by insulating bonds into a plurality of track sections, the train is continuously controlled by means of signals induced in inductive pick up means on the train by current flow in the track sections. Alternating current at code rates of 180, 120 and 75 cycles/min., signal, respectively, fast (30 m.p.h.), medium (15 m.p.h.) and slow (7 m.p.h.) speeds, a code rate of 37 1/2 cycles/min. signals a full service application of the brakes and a steady D.C. code, or the absence of a code, signals an emergency stop. The track arrangement, Figs. 1A-1H, 1J and 1K (not shown) comprises a single stretch of track divided into eight sections each of which is provided at its ends with means for applying a code signal to the section and for detecting the presence of a code signal in the section. The stretch extends between passing sidings which are also divided into sections and provided with code applying and detecting means. Each siding is protected by an approach signal and by main line and siding entry and exit signals which with the siding track switches are controlled from a central office. Normally, with no train present, a code is established for east bound traffic by the application of a steady D.C. signal to the most westerly section, section No. 8. This is detected at the eastern end of this section and operates on coding apparatus to apply a 37 1/2 code to the adjacent end of section 7 which on being detected at the other end of the section applies 75 code rate to section 6 and so on through the sections. The reception of a code rate at the first section being effective to prevent the set up of a similar code sequence in the opposite direction. The setting up of a route through the system by the control office is effective to reverse the sequence for west bound traffic and to modify the rate frequency as required e.g. in approach to signals and where the route passes over track switches set to reverse. In addition the setting up is effective to apply the required code rate signals to the sections forming the passing sidings. The track signal is picked up by coils RC on the train and effects pick up, in dependence on its frequency, of one of the rate relays 37 1/2R, 75R, 120R or 180R and its associated repeater relay RP. In the absence of a signal a stick circuit for relay EMP is released and braking apparatus EMV is de-energized to initiate an emergency stop. A wheel operated generator AG provides a signal having a frequency proportional to the train speed which is applied to a circuit including high pass filters HS2.5 to HS32 and relays 2.5S to 32S to energize each relay when the train speed in m.p.h. exceeds the designation number of the relay e.g. relay 30S is energized when the speed exceeds 30 m.p.h. The generator signal is also applied, via amplifier A2 to the overspeed filter circuit OF2-OF34 selected by a front contact of the energized route relay. Oscillator OSC provides an output at a frequency which is sufficiently high to pass any of the overspeed filters OF2 &c. and this output energizes relay D via amplifier A1. Relay DP is energized via a front contact of relay D and in picking up switches off the oscillator OSC. This continuous pulsing of relay DP energizes overspeed relay C. Assume the train, when at a standstill, receives code rate 180, relays 180R and 180RP are energized and relay EPVR is picked up and energizes magnet valve SMV to release the train brakes and timer T2 to prevent a full throttle application. Throttle wire TH2 is now energized and the train starts to move, when timer T2 completes its timing operation relay T2P is operated and throttle wire TH3 is energized. As the speed of the train increases relay 2.58 is picked up and the throttle wire TH4 is energized. In this manner the throttle setting is increased to full throttle as successive speed relays pick up, until relay 28S is energized when the setting is reduced. If the train speed increases above 32 m.p.h. (relay 32S energized) the setting is switched to " idle " by energizing throttle wire TH1. If the speed increases above 34 m.p.h. the output of the axle driven frequency generator is effective to produce an output from overspeed filter OF34 which steadily energizes relay D. This results in a dropping away of overspeed relay C which de-energizes relay EPVR to produce a service application of the brakes for the period of operation of timer T1. Assuming that at the end of the timing period the speed is below 34 m.p.h. relays D and DP return to their pulsing condition, relay C is re-energized and the brake application is removed.